Is it OK if watchdog timer is cleared amid timer interrupt processing?

Question:

The watchdog timer is used to prevent CPU lockup. To simplify the program, the watchdog timer is cleared during the periodical timer interrupt processing.
Is this OK?

Answer:

We do not recommend that the watchdog timer be cleared during timer interrupt processing, because even if the main routine is locked up in this system, if a timer interrupt is acknowledged, the watchdog timer will be cleared and the system cannot detect a CPU lockup.